feat: pivot to AI-native task management platform (#232)

Replace the agent framework codebase with a new monorepo structure
for an AI-native Linear-like product where agents are first-class citizens.

New architecture:
- server/ — Go backend (Chi + gorilla/websocket + sqlc)
  - API server with REST routes for issues, agents, inbox, workspaces
  - WebSocket hub for real-time updates
  - Local daemon entry point for agent runtime connection
  - PostgreSQL migration with 13 tables (issue, agent, inbox, etc.)
  - WebSocket protocol types for server<->daemon communication
- apps/web/ — Next.js 16 frontend
  - Dashboard layout with sidebar navigation
  - Route skeleton: inbox, issues, agents, board, settings
- packages/ui/ — Preserved shadcn/ui design system (26+ components)
- packages/types/ — Full API contract types (Issue, Agent, Workspace, Inbox, Events)
- packages/sdk/ — REST ApiClient + WebSocket WSClient
- packages/store/ — Zustand stores (issue, agent, inbox, auth)
- packages/hooks/ — React hooks (useIssues, useAgents, useInbox, useRealtime)
- packages/utils/ — Shared utilities

Removed: apps/cli, apps/desktop, apps/mobile, apps/gateway,
packages/core, skills/, and all agent-framework code.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

.env.example

@@ -1,9 +1,15 @@
-# Telegram Bot
-# Get a token from @BotFather on Telegram
-TELEGRAM_BOT_TOKEN=
+# Database
+DATABASE_URL=postgres://multica:multica@localhost:5432/multica?sslmode=disable
 
-# Optional: webhook secret token for production
-# TELEGRAM_WEBHOOK_SECRET_TOKEN=
+# Server
+PORT=8080
+JWT_SECRET=change-me-in-production
 
-# Optional: webhook URL (if not set, uses long-polling mode for local dev)
-# TELEGRAM_WEBHOOK_URL=https://your-domain.ngrok-free.dev/telegram/webhook
+# Google OAuth
+GOOGLE_CLIENT_ID=
+GOOGLE_CLIENT_SECRET=
+GOOGLE_REDIRECT_URI=http://localhost:3000/auth/callback
+
+# Frontend
+NEXT_PUBLIC_API_URL=http://localhost:8080
+NEXT_PUBLIC_WS_URL=ws://localhost:8080/ws